The present invention is directed to a composite envelope composed of at least one heat-shrinkable foil and using reinforcements composed of tear-resistant fibers.
European Application 0 115 905 discloses a heat-readjustable or shrinkable object which is composed of shrinkable fabrics having shrinkable threads or fibers composed of cross-linked polymers, which are stretched and, thus, heat-readjustable or shrinkable. In addition, high-strength threads composed of polyester or glass can be woven into this fabric. However, a disadvantage of this device is that the tensile strength of the heat-shrinkable threads or fibers are extremely low exactly at the shrinking temperature. In addition, the risk exists that along the threads of the fibers, cavities can develop into which moisture will penetrate.